The toolkit that NuPattern builds for you is a standard VSIX extension. VSIX extensions are the mechanism by which all VS extensions are deployed since VS2010.
There are other old fashioned ways to deploy VS extensions (VSPackages) but these are becoming obsolete.

The VSIX that NuPattern builds for you has embedded in it the NuPattern extension. (see your source.extension.vsixmanifest file in your toolkit project for how that is done)

VSIX extensions are then published as single file downloads, that you can put online in a public gallery, like the VSGallery (visualstudiogallery.microsoft.com) or somewhere in your company network (private galleries)

You have two options if you want to package/deploy your toolkit as part of another VSIX extension. You can either embed the VSIX binary within the containing VSIX extension, or you can reference it (by URL) from the containing VSIX. In either case, you are
creating a dependency on the embedded/referenced VSIX, and stating that it needs to be installed before the containing VSIX can be installed. The VSIX installer will do that for you if you embed the VSIX. Otherwise, it will fail.

does that help, or are you looking for actual examples of how to do all this?